Thanks Matt for your detailed and structured reply. I really appreciate your tons of replies! I forgot to look into the UserManager class which is useful for understanding.
In addition, I'd like to provide a few links I came across the other day: 1. A paper about jMock taken at jmock.org: http://www.jmock.org/oopsla2004.pdf 2. A presentation on testing techniques in J2EE: http://www.chrisrichardson.net/javaone2007.html 3. An article on ServerSide.com http://www.theserverside.com/tt/articles/article.tss?l=JMockTestDrivenDev Martin mraible wrote: > > In the tutorial, I can understand why it's confusing. In the example, > you're not really testing anything but that a method is being called. > You might think this is silly, but it's actually saved my ass in the > past. Also, what happens when your one-line method turns into a > 200-line one that talks to EJBs on another server and a web service on > a legacy system. It's nice to be able to mock those dependencies. > Overengineering? Possibly. > > We should probably add some verbage to explain it more. Testing with > mocks makes a lot of sense in a few cases: > > 1. You want speed. > 2. You want to test a single class, not it's dependencies. > 3. You want to test business logic in a method. > 4. You want to segregate development teams. > > #1. This is pretty obvious - not connecting to a database or > initializing Spring will be very fast. > > #2. If you write an "integration" test instead of a mock test, > changes are you'll be doing the same thing as the DAO test does, > except you'll be verifying the Spring wiring is correct. With > integration testing, the class you're testing is often like a black > box, where you put in inputs and expect outputs. With mock testing, > you have a bit more control and can set expectations on dependencies > to make sure methods are called and such. > > #3. This doesn't make much sense until your managers have lots of > business logic. Of course, integration tests on a manager with > one-line methods is similar in its usefullness. Of course, there's > nothing stopping you from writing integration tests for managers. In > fact, there's a BaseManagerTestCase to do just that. See > UserManagerTest.java for an example: > > http://static.appfuse.org/appfuse-service/xref-test/org/appfuse/service/UserManagerTest.html > > #4. If you have a UI team that wants to be decoupled from the backend, > you can provide them with interfaces they can mock. Then they don't > have to be concerned about the backend - they can tell it what they > want it to return. > > Spring AutoMock (http://sourceforge.net/projects/automock) could be > useful as well - allowing you to mock out the backend when running in > a servlet container. At least, I think that's the functionality it > provides. > > Hope this helps, > > Matt > > On 9/19/07, Martin Homik <[EMAIL PROTECTED]> wrote: >> >> I do understand that mocks are useful to imitate a certain behaviour of >> compononts which are sort of resource-demanding. But, I don't get the >> value >> of using jMock for testing Managers as it is used in the tutorial. Let me >> pick a test method: >> >> >> public void testFindByLastName() { >> log.debug("testing findByLastName"); >> >> List people = new ArrayList(); >> String lastName = "Smith"; >> >> // set expected behavior on dao >> dao.expects(once()).method("findByLastName") >> .with(eq(lastName)) >> .will(returnValue(people)); >> >> List result = manager.findByLastName(lastName); >> assertSame(people, result); >> } >> >> As far as I understand it, I am telling the mock (for PersonManagerDao) >> that >> if a method "findByLastName" is invoked with a parameter "lastName", then >> it >> should return the empty ArrayList "people". In a second step the manager >> just invokes this method and the mock returns "people" which is stored in >> "result". Now, comparing "people" with "result" does not make much sense >> and >> unsurprisngly both lists must be the same. It looks like the following >> conversation: >> >> ME: "If I ask you for your name then answer 'Arthur'. So what's your >> name?". >> Arthur: "My name is Arthur." >> ME: "You're right." >> >> I have the deep impression that I misunderstand something, but I am >> unable >> to identify my knowledge gap. Can anyone help and explain jMock's use in >> the >> tutorial? >> >> I can imagine to use jMock in the following way: I have some method which >> is >> doing some computation which depends on information being stored in a >> database. Let's assume I want to calculate the length of someone's first >> name. Then with jMock I can simulate the database's behaviour. But, >> instead >> of testing the retrieval function, I want to test the computation. Any >> idea >> what the test would look like? >> >> Cheers, >> Martin >> >> -- >> View this message in context: >> http://www.nabble.com/jMock-in-Tutorial-not-self-explaining-tf4481302s2369.html#a12778467 >> Sent from the AppFuse - User mailing list archive at Nabble.com. >> >> --------------------------------------------------------------------- >> To unsubscribe, e-mail: [EMAIL PROTECTED] >> For additional commands, e-mail: [EMAIL PROTECTED] >> >> > > > -- > http://raibledesigns.com > > --------------------------------------------------------------------- > To unsubscribe, e-mail: [EMAIL PROTECTED] > For additional commands, e-mail: [EMAIL PROTECTED] > > > -- View this message in context: http://www.nabble.com/jMock-in-Tutorial-not-self-explaining-tf4481302s2369.html#a12793435 Sent from the AppFuse - User mailing list archive at Nabble.com. --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
